okay puzzled here. Jag has been running fine. Now when I crank from cold, i get rough running and idling, car shakes. It is NOT tensioners or timing, we've already done tensioners and it ran fine after that. Last night it did this, then an hour later we cranked it and it ran smooth as silk, no shakes, no restricted performance light. Now its doing it again. Restricted performance, rough idle and shakes. I know on the 3rd or 4th try it will dissappear and run fine. Plugs are a month old. I know the gaskets are old and we have them on order as we see a little oil leaking on the mainifold. We took carb cleaner on a rag and cleaned the throttle body opening and butterfly, checked all the connections, MAF sensor and part breather openings. What next? Yes i have check engine light but its been on since I got the car and its been running fine. Where are the O2 sensors? I have unplugged connections to the throttle body and reconnected as well. Anyone have any ideas? While its running like this I smell like a rich gas smell, like the car is getting too much fuel. Would this be TB rebuild time? Want to know what to check to make sure its not a sensor before doing that. Thanks.

 

What's the engine type and year of the car? Is it 3.2, 4.0 or Supercharged 4.0? Try cleaning the TPS (throttle position sensor) and try to wait a few seconds on ignition before starting the car (until all lights on the dash disappears).

I have similar problems with my own Jag... if you want, have a look at my thread - maybe you'll find answers for yourself: https://www.jaguarforums.com/forum/x...mileage-70921/

Try finding the reason for the Check Engine light - IT IS NOT NORMAL to drive the car in like this. Try connecting an OBDII reader to check if you have active or stored faults. If you are in US there some places (workshops) where you can have your car tested with computer for free. When you get the codes - tell us what it is... this way it'll be much easier to find where your problem is coming from.

Wish you all the best and welcome to big XJ family

 

i read your threads last night and alot of others. I have the original TB on this 98 xj8 with 192K miles. I bought the car 2 months ago with tensioner issues. Car runs fine just needs a lil TLC. It's been running fine until yesterday it started with this. Everything I have read leans to either a coil pack intermittenly working or the TB. I have tried cleaning the TB but where is sthe TB sensor? Where are the o2 sensors? When its doing its thing with the rough idle I smell a rich fuel smell. Then miraculously you can turn it off, wait and recrank and its running fine after the engine has warmed up. Its' insane! LOL. Any help would be appreciated. I really am not wanting to have to have the TB rebuilt but if I have to I guess I have to. I jsut want to rule out all other possibilities first.

 

Coastal - buy a cheap code reader. Then pull the codes and post here, it's all guesswork until you report the fault the car has logged.

And welcome from me too.

 

forgot to say waiting on the code reader. Purchased it 2 days ago on ebay so of course it will. Weird thing is I can crank it and its got the restricted performance and rough idle. I can turn it off and unplug and plug in the coil packs on the driver side and then go in and crank it and its fine! I'm going to keep playing with it until maybe i can narrow it down. it's acting like a bad coil pack maybe until I get the code reader.

 

So whatever happened with your issue?/ What did you find?

 

sayitaintso, You are posting to a thread that is five years old. Probably doesn't even have the car anymore.
If you are having problems post a new thread and we can try to help you out.